National Snow and Ice Data Center in the context of "Ocean Climate Laboratory"

The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately 14,060,000 km (5,430,000 sq mi) and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea or North Polar Sea. It has also been described as an estuary of the Atlantic Ocean. It is also seen as the northernmost part of the all-encompassing world ocean.

The Arctic Ocean includes the North Pole region in the middle of the Northern Hemisphere and extends south to about 60°N. The Arctic Ocean is surrounded by Eurasia and North America, and the borders follow topographic features: the Bering Strait on the Pacific side and the Greenland Scotland Ridge on the Atlantic side. It is mostly covered by sea ice throughout the year and almost completely in winter. The Arctic Ocean's surface temperature and salinity vary seasonally as the ice cover melts and freezes; its salinity is the lowest on average of the five major oceans, due to low evaporation, heavy fresh water inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities. The summer shrinking of the ice has been quoted at 50%. The US National Snow and Ice Data Center (NSIDC) uses satellite data to provide a daily record of Arctic sea ice cover and the rate of melting compared to an average period and specific past years, showing a continuous decline in sea ice extent. In September 2012, the Arctic ice extent reached a new record minimum. Compared to the average extent (1979–2000), the sea ice had diminished by 49%.

Sea ice in the Arctic region has declined in recent decades in area and volume due to climate change. It has been melting more in summer than it refreezes in winter. Global warming, caused by greenhouse gas forcing is responsible for the decline in Arctic sea ice. The decline of sea ice in the Arctic has been accelerating during the early twenty-first century, with a decline rate of 4.7% per decade (it has declined over 50% since the first satellite records). Summertime sea ice will likely cease to exist sometime during the 21st century.

The region is at its warmest in at least 4,000 years. Furthermore, the Arctic-wide melt season has lengthened at a rate of five days per decade (from 1979 to 2013), dominated by a later autumn freeze-up. The IPCC Sixth Assessment Report (2021) stated that Arctic sea ice area will likely drop below 1 million km in at least some Septembers before 2050. In September 2020, the US National Snow and Ice Data Center reported that the Arctic sea ice in 2020 had melted to an extent of 3.74 million km, its second-smallest extent since records began in 1979. Earth lost 28 trillion tonnes of ice between 1994 and 2017, with Arctic sea ice accounting for 7.6 trillion tonnes of this loss. The rate of ice loss has risen by 57% since the 1990s.

The Exchange for Local Observations and Knowledge of the Arctic, is an Arctic research data management program that combines local traditional knowledge (LTK) and local observations data from Indigenous Arctic residents utilizing effective and appropriate western methods to properly share Arctic Indigenous Knowledge. The LTK data the program stewards consists of observations of sea ice, weather, wildlife and comes in many forms such as written interview transcripts, audio or video tapes and files, photographs, artwork, illustrations and maps.Housed at the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder Cooperative Institute for Research and Environmental Sciences (CIRES), ELOKA is a National Science Foundation (NSF) Arctic Observing Network (AON) research program that came out of the 2007-2008 International Polar Year (IPY).

Mark Clifford Serreze (born 1960) is an American geographer and the director (since 2009) of the National Snow and Ice Data Center (NSIDC), a project of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. In 2019, he was named a Distinguished Professor in the Department of Geography. Serreze is primarily known for his expertise in the Arctic sea ice decline that has occurred over the last few decades due to global warming, a topic about which he has expressed serious concern. He has authored over 150 peer-reviewed publications.